1. Field of the Invention
The present invention relates to an oil separator for separating oil from gas and a cooling-cycle apparatus using the oil separator, and more particularly, to an oil separator for separating oil from gas in a cyclone separation manner, and a cooling-cycle apparatus using the oil separator.
2. Description of the Related Art
As well known to those skilled in the art, a cooling-cycle apparatus is an apparatus installed in an air conditioner, refrigerator, etc. for cooling or warming a room, or keeping food at low temperatures.
FIG. 1 is a diagram of a conventional cooling-cycle apparatus.
As shown in FIG. 1, the cooling-cycle apparatus comprises a compressor 2, a condenser 4, an expander 6, an evaporator 8, and refrigerant conveyance tubes 9. The compressor 2 compresses a gaseous refrigerant having a low-temperature and low-pressure to a high-temperature and high-pressure gas, and the condenser 4 condenses the high-temperature and high-pressure gaseous refrigerant to a liquid by taking heat from the gaseous refrigerant. The liquefied high-temperature and high-pressure refrigerant is depressurized by means of the expander 6 to a two-phase refrigerant. Here, the two-phase refrigerant is a mixture of gas and liquid and has a low-pressure and low-temperature. The depressurized refrigerant flows into the evaporator 8, and is then vaporized while absorbing heat from air around the evaporator 8. The compressor 2, the condenser 4, the expander 6 and the evaporator 8 are connected to one another by way of the refrigerant conveyance tubes 9 to enable the refrigerant to circulate therethrough.
The compressor 2 comprises a compression unit having a refrigerant compression chamber, a motor unit for driving the compression unit, and an oil pump for the lubrication of both the compression unit and the motor.
Installed between the compressor 2 and the condenser 4 is an oil separator 10. The oil separator 10 serves to separate oil, discharged from the compressor 2 as shown in a dash-lined arrow, from the gaseous refrigerant, likewise discharged from the compressor 2 as shown in solid-lined arrows.
Not described reference numeral 2a designates an accumulator, which is mounted at the refrigerant conveyance tube 9 near an inlet of the compressor 2. The accumulator 2a is adapted to catch the liquefied refrigerant, not evaporated in the evaporator 8, so as to prevent it from flowing into the compressor 2.
FIG. 2 is a longitudinal sectional view illustrating the conventional oil separator.
The oil separator 10 comprises a casing 12 defining an interior space, an inflow tube 14 for supplying the oil and the gaseous refrigerant into the casing 12, a filtering member 16 mounted in an intermediate region of the casing 12 and adapted to filter oil while allowing the passage of the gaseous refrigerant, causing the filtered oil to drop into a lower region of the casing 12, an oil outflow tube 18 for delivering the dropped oil in the lower region of the casing 12 to the compressor, and a refrigerant outflow tube 20 for supplying the refrigerant, passed through the filtering member 16, to the condenser.
Now, the operation of the conventional cooling-cycle apparatus configured as stated above will be explained.
When the compressor 2 starts to drive, the high-temperature and high-pressure gaseous refrigerant (shown in the solid-line arrows) and the oil (shown in the dash-lined arrow) are simultaneously discharged from the compressor 2, and then are supplied into the casing 12 of the oil separator 10 through the inflow tube 14.
Within the casing 12 of the oil separator 10, the oil collides with the filtering member 16 and forms oil droplets. The oil droplets are easy to drop into the lower region of the casing 12 by gravity, and then return back to the compressor 2 through the oil outflow tube 18.
Meanwhile, the gaseous refrigerant, supplied into the casing 12 of the oil separator 10, is discharged through the refrigerant outflow tube 20 after passing through the filtering member 16.
The gaseous refrigerant, discharged from the outflow tube 20, is condensed while passing through the condenser 4 by discharging heat thereof to the outside, and is successively depressurized while passing through the expander 6 to a two-phase, namely, liquid-containing gaseous refrigerant having a low-pressure and low-temperature. The depressurized two-phase refrigerant flows into the evaporator 8 and is then vaporized by absorbing heat from air around the evaporator 8. Finally, the gaseous refrigerant returns to the compressor 2.
The above described conventional oil separator 10 having a configuration in that the filtering member 16 is mounted therein to filter the oil from the gaseous refrigerant, however, suffers from increased manufacturing costs and complicated installation operation due to the existence of the filtering member 16, and also has a limitation to reduce the overall size thereof. Furthermore, the filtering member 16 fails to completely intercept the passage of the oil, resulting in a low degree of oil separation efficiency.
Accordingly, with the use of the oil separator as stated above, part of the oil supplied into the casing 12 passes through the filtering member 16 and inevitably circulates through the cooling-cycle apparatus together with the refrigerant, causing only a small amount of the oil to return to the compressor 2 through the oil separator 10 and the oil outflow tube 18. This requires filling the cooling-cycle apparatus with an excessive amount of oil over an appropriate value. The greater the amount of the oil circulating through the cooling-cycle apparatus, the lower the efficiency of the cooling-cycle apparatus.